YouTube Video Stats API

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already mark it read-only, and the description adds meaningful behavior beyond that: live reads cost 1 credit while cache hits are free, returned fields use the platform's own names, and only public data is accessible. No contradiction with the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is compact, front-loads the main purpose, and keeps cost/data scope in short sentences. The final 'Read-only' is redundant with the readOnlyHint annotation, which keeps it from a perfect score.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple two-parameter read-only tool, the description covers purpose, return shape, cost behavior, and data scope. There is no output schema, but the main return values are stated clearly enough for an agent to invoke and interpret results.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, with the url parameter explained by example and the cache parameter stating its default and cost behavior. The description adds no parameter-level meaning beyond the schema, so the baseline of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description names a specific verb-resource pair: it returns view, like, and comment counts for a single public YouTube video or Short. It also signals granularity via 'Returns one object,' which distinguishes it from list- or channel-level siblings like youtube_channel and youtube_videos.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It clearly scopes use to public video/Short stats and explicitly excludes profile-like or non-public data, saying there are 'no bios, contact details or login-walled data.' It does not name an alternative tool for channel-level stats, so it stops short of the explicit routing that would merit a 5.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.